1. Technical Field
The present invention relates to liquid ejecting heads and liquid ejecting apparatuses that eject liquid through nozzle openings and, in particular, to ink jet recording heads and ink jet recording apparatuses that discharge ink as liquid.
2. Related Art
An ink jet recording head making use of flexural deformation of a piezoelectric actuator that is configured of a lower electrode, a piezoelectric layer and an upper electrode, has been put to practical use. In such ink jet recording head, part of a pressure generation chamber communicating with a nozzle opening is configured by a vibration plate, the vibration plate is deformed by the piezoelectric actuator as a piezoelectric element to pressurize ink in the pressure generation chamber, and consequently an ink droplet is discharged through the nozzle opening.
Further, a drive circuit is mounted on a wiring substrate, such as a printed substrate or the like, that supplies a drive signal to drive the piezoelectric actuator; the drive signal from the drive circuit is supplied to the piezoelectric actuator via the wiring (for example, see JP-A-2006-281477).
With increase in the number and density of nozzle rows, ink jet recording heads equipped with a plurality of piezoelectric actuators are required. However, if a conductive connection area of a connection portion that connects a common electrode common to a plurality of piezoelectric actuators with a wiring of a wiring substrate is small, electric resistance thereof is increased so as to cause a voltage drop and the like when the plurality of piezoelectric actuators are driven at the same time. As a result, a sufficiently high voltage cannot be applied due to the voltage drop such that there arises a problem of causing a driving failure.
In addition, if the electric resistance of the connection portion that connects the common electrode of the piezoelectric electrodes with the wiring of the wiring substrate becomes larger, heat is generated in the connection portion. This causes another problem to arise, i.e., a breakdown such as peeling-off of the wiring substrate is likely to happen.
Furthermore, if the area of a terminal portion is enlarged so as to enlarge the area of a connection portion that conducts electricity between the common electrode of the piezoelectric actuators and a wiring of an external wiring circuit, a problem arises such that an ink jet recording head becomes larger.